Resources, Conservation and Recycling 65 (2012) 124–129 Contents lists available at SciVerse ScienceDirect Resources, Conservation and Recycling journa l h o me pag e: www.elsevier.com/locate/resconrec Full length Article Rainwater treatment in airports using slow sand filtration followed by chlorination: Efficiency and costs Ronan Fernandes Moreira Neto, Maria Lúcia Calijuri, Isabella de Castro Carvalho ∗ , Aníbal da Fonseca Santiago Federal University of Vic ¸ osa, Department of Civil Engineering, Environmental Research Group, P.H. Rolfs, s/n, Campus Universitário, Vic ¸ osa – MG 36570-000, Brazil a r t i c l e i n f o Article history: Received 24 February 2012 Received in revised form 20 April 2012 Accepted 1 June 2012 Keywords: Rainwater treatment Airports Alternative water sources Rational water use Slow sand filtration a b s t r a c t Water scarcity is a reality worldwide, either by quantitative or qualitative unavailability. The search for alternative water sources, water reuse and other mechanisms for its rational use is a global trend. Considering these facts, rainwater use is an interesting alternative to complement non-potable demand in locations such as airport complexes. These environments present large roof areas and support different activities which consume non-potable water, making them potential sites for the installation of rainwater use systems. The objectives of this research were to assess rainwater quality in an airport environment, study the performance of slow sand filtration followed by chlorination in the treatment of rainwater and analyze treatment costs. The study was carried out in a mid-size airport in Brazil. The proposed system provided water with physical, chemical and microbiological quality consistent with recommendations for reuse and the price per treated cubic meter was 60% lower than the price paid to the current water supply company. © 2012 Elsevier B.V. All rights reserved. 1. Introduction Water shortage is an important issue worldwide, and the increasing complexity of the relationship between conflicting water uses and the offer of good-quality water is a challenge for many countries. As a consequence, rainwater use practices are becoming increasingly important instruments for reducing potable water demand in order to prioritize its use for more restrictive activities such as public supply, as suggested by Basinger et al. (2010). Airports consume significant amounts of water in order to main- tain their infrastructure and operational routine. However, these environments usually have large roof areas which make them potential sites for the implementation of rainwater use systems. The efficiency and feasibility of such systems have been studied by several authors (Bauer, 2011; Domènech and Saurí, 2010; Jones and Hunt, 2010; Li et al., 2010; Mendez et al., 2011; Mierzwa et al., 2007; Tomaz, 2009). They say that rainwater quality depends on the atmospheric characteristics of the region, the presence/absence of trees and birds, and also the type and conditions of the rainwater catchment surface. ∗ Corresponding author. Tel.: +55 31 38993098; fax: +55 31 38993093. E-mail addresses: r9neto@yahoo.com.br (R.F. Moreira Neto), calijuri@ufv.br (M.L. Calijuri), isakpi@yahoo.com.br (I.d.C. Carvalho), anibalsantiago@gmail.com (A.d.F. Santiago). In general, because of the risk of contamination by microor- ganisms and several chemical substances, rainwater requires some type of treatment prior to its utilization. The level of treatment to be applied depends mostly on the intended use (potable or not) and the quality of the rainwater collected from roofs or other surfaces (Helmreich and Horn, 2009). Technologies such as slow sand filtration and chlorination are traditional low-cost methods which have been used successfully for decades to improve the bacteriological quality of water for public supply (Brasil, 2006a; Dryden, 2007; Fewster et al., 2004; Karon et al., 2011). Bauer (2011) describes removal of Escherichia coli (E. coli) between 2.25 and 3.92 logarithmic units by slow sand filtration. Timms et al. (1995) found that the slow sand filtration technique is highly efficient, with better than 99.997% reduction in Cryptosporidium oocyst levels. Heller et al. (2006) evaluated slow sand filters treating synthetic water enriched with Cryptosporid- ium oocysts and found removal efficiencies between 99.988 and 99.998%. Keraita et al. (2008) operated slow sand filters treating domestic wastewater and found removals of 2 logarithmic units for fecal coliforms, from 2.3 to 3.7 logarithmic units for E. coli and 2.6 logarithmic units for Enterococcus, depending on the quality of the raw water and the application rate. The objectives of this study were to assess the quality of rain- water in a mid-size international airport in Brazil as well as the performance and costs of its treatment using slow sand filtration followed by chlorination in order to evaluate the replicability of this technology to other airports. It is important to consider that 0921-3449/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.resconrec.2012.06.001